1. Field of the Invention
The present invention relates to an abrupt opening apparatus of a pressurized chamber in an intended procedure to accomplish thrust termination of the solid rocket motor.
2. Background of the Related Art
In general, the solid rocket motor comprises a combustion chamber which contains the propellant initially, and a nozzle for generating propulsion by accelerating the gas produced from the combustion in the chamber. In this regard, if the gas is accelerated in the nozzle, thrust is produced in the direction opposing to the accelerated direction of the gas by means of the retroaction to thereby propel the flight vehicle.
The thrust control of a solid rocket motor is very difficult in comparison to a liquid rocket engine. Thrust termination by abrupt opening of ports formed at the front of a combustion chamber during the combustion is one of the thrust controls of solid rocket motor.
When the rocket motor provided with the thrust termination device as described above is schematically reviewed, it comprises a combustion chamber with a solid propellant built-in; a nozzle mounted at the rear of the combustion chamber; a dome formed at the front side of the combustion chamber; an igniting device mounted at the center of the dome; and a plurality of thrust termination devices mounted at the dome of the combustion chamber.
During the combustion the thrust termination port undergoes combustion pressure and is maintained to be closed by the thrust termination device. When the command of thrust termination is practiced, the thrust termination ports are opened and the ports act like as other nozzles for a time, then combustion is broke up as the pressure of the combustion chamber drops radically.
Conventionally, a Pyrotechnic devices (explosion bolt) described in U.S. Pat. No. 5,400,713 are mostly used in the thrust termination device.
In this regard, it is required for the thrust termination device to be sufficiently safe in structure before the operation, operated rapidly at the operation and reproduced completely. However, when the thrust termination device such as the pyrotechnic device was operated, there were produced substantially big impacts, and fragments of the operated device were dispersed, so that the missile had to be affected from the substantial impact during the operation of the thrust termination device to thereby affect badly to the flying stability of the missile and the precision of the control after the thrust termination.
Accordingly, it is very important to reduce the magnitude of impacts at the time of the operation of the thrust termination device.